Fluid and Electrolyte Transport across the Peritoneal Membrane during CAPD According to the Three-pore Model

2004 ◽  
Vol 24 (1) ◽  
pp. 10-27 ◽  
Author(s):  
Bengt Rippe ◽  
Daniele Venturoli ◽  
Ole Simonsen ◽  
Javier De Arteaga
Keyword(s):  
Peritoneal Dialysis ◽  
Ion Transport ◽  
Electrolyte Transport ◽  
Ion Concentration ◽  
Concentration Gradients ◽  
Pore Model ◽  
Ultrafiltration Failure ◽  
High Initial Concentration ◽  
The Impact ◽  
Convection Dominated

In the present review, we summarize the principles governing the transport of fluid and electrolytes across the peritoneum during continuous ambulatory peritoneal dialysis (CAPD) in “average” patients and during ultrafiltration failure (UFF), according to the three-pore model of peritoneal transport. The UF volume curves as a function of dwell time [V( t)] are determined in their early phase by the glucose osmotic conductance [product of the UF coefficient (LpS) and the glucose reflection coefficient (σg)] of the peritoneum; in their middle portion by intraperitoneal volume and glucose diffusivity; and in their late portion by the LpS, Starling forces, and lymph flow. The most common cause of UFF is increased transport of small solutes (glucose) across the peritoneum, whereas the LpS is only moderately affected. Concerning peritoneal ion transport, ions that are already more or less fully equilibrated across the membrane at the start of the dwell, such as Na+ (Cl–), Ca2+, and Mg2+, have a convection-dominated transport. The removal of these ions is proportional to UF volume (approximately 10 mmol/L Na+ and 0.12 mmol/L Ca2+ removed per deciliter UF in 4 hours). The present article examines the impact on fluid and solute transport of varying concentrations of Ca2+ and Na+ in peritoneal dialysis solutions. Particularly, the effect of “ultralow” sodium solutions on transport and UF is simulated and discussed. Ions with high initial concentration gradients across the peritoneum, such as K+, phosphate, and bicarbonate, display a diffusion-dominated transport. The transport of these ions can be adequately described by non-electrolyte equations. However, for ions that are in (or near) their diffusion equilibrium over the peritoneum (Na+, Ca2+, Mg2+), more complex ion transport equations need to be used. Due to the complexity of these equations, however, non-electrolyte transport formalism is commonly employed, which leads to a marked underestimation of mass transfer area coefficients (PS). This can be avoided by determining the PS when transperitoneal ion concentration gradients are steep.

scholarly journals Outcomes of Peritoneal Dialysis Patients and Switching to Hemodialysis: A Competing Risks Analysis

2014 ◽  
Vol 34 (3) ◽  
pp. 289-298 ◽  
Author(s):  
Jernej Pajek ◽  
Alastair J. Hutchison ◽  
Shiv Bhutani ◽  
Paul E.C. Brenchley ◽  
Helen Hurst ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Residual Renal Function ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Adjusted Analysis ◽  
Ultrafiltration Failure ◽  
The Impact ◽  
Technique Failure

BackgroundWe performed a review of a large incident peritoneal dialysis cohort to establish the impact of current practice and that of switching to hemodialysis.MethodsPatients starting peritoneal dialysis between 2004 and 2010 were included and clinical data at start of dialysis recorded. Competing risk analysis and Cox proportional hazards model with time-varying covariate (technique failure) were used.ResultsOf 286 patients (median age 57 years) followed for a median of 24.2 months, 76 were transplanted and 102 died. Outcome probabilities at 3 and 5 years respectively were 0.69 and 0.53 for patient survival (or transplantation) and 0.33 and 0.42 for technique failure. Peritonitis caused technique failure in 42%, but ultrafiltration failure accounted only for 6.3%. Davies comorbidity grade, creatinine and obesity (but not residual renal function or age) predicted technique failure. Due to peritonitis deaths, technique failure was an independent predictor of death hazard. When successful switch to hemodialysis (surviving more than 60 days after technique failure) and its timing were analyzed, no adverse impact on survival in adjusted analysis was found. However, hemodialysis via central venous line was associated with an elevated death hazard as compared to staying on peritoneal dialysis, or hemodialysis through a fistula (adjusted analysis hazard ratio 1.97 (1.02 – 3.80)).ConclusionsOnce the patients survive the first 60 days after technique failure, the switch to hemodialysis does not adversely affect patient outcomes. The nature of vascular access has a significant impact on outcome after peritoneal dialysis failure.

scholarly journals Volume Stress-Induced Peritoneal Endothelin-1 Release in Continuous Ambulatory Peritoneal Dialysis

1999 ◽  
Vol 10 (12) ◽  
pp. 2585-2590
Author(s):  
STANISLAO MORGERA ◽  
SIMONE KUCHINKE ◽  
KLEMENS BUDDE ◽  
ANDREAS LUN ◽  
BERTHOLD HOCHER ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
Peritoneal Membrane ◽  
Endothelin 1 ◽  
Target Values ◽  
Ultrafiltration Failure ◽  
Significant Difference ◽  
The Impact ◽  
Volume Stress

Abstract. In long-term peritoneal dialysis, functional deterioration of the peritoneal membrane is often associated with proliferative processes of the involved tissues leading to peritoneal fibrosis. In continuous ambulatory peritoneal dialysis (CAPD), failure to achieve target values for adequacy of dialysis is commonly corrected by increasing dwell volume; in case of ultrafiltration failure, osmolarity of the dialysate gets increased. In a prospective study, the impact of increasing dwell volume from 1500 ml to 2500 ml per dwell (volume trial) or changing the osmolarity of the dialysate from 1.36 to 3.86% glucose (hyperosmolarity trial) on the peritoneal endothelin-1 (ET-1) release was analyzed. ET-1 is known to exert significant proliferative activities on a variety of cell types leading to an accumulation of extracellular matrix. A highly significant difference in the cumulative peritoneal ET-1 synthesis was found between the low- and high-volume exchange, whereas differences in the hyperosmolarity setting were only moderate. Sixty minutes after initiating dialysis, the cumulative ET-1 synthesis was 2367 ± 1023 fmol for the 1500 ml versus 6062 ± 1419 fmol for the 2500 dwell (P < 0.0001) and 4572 ± 969 fmol versus 6124 ± 1473 fmol for the 1.36 and 3.86% glucose dwell (P < 0.05), respectively. In conclusion, increasing dwell volume leads to a strong activation of the peritoneal paracrine endothelin system. Because ET-1, apart from being a potent vasoactive peptide, contributes to fibrotic remodeling, this study indicates that volume stress-induced ET-1 release might contribute to structural alteration of the peritoneal membrane in long-term peritoneal dialysis.

Electrical potential profile in rabbit ileum: role of rheogenic Na transport.

1977 ◽  
Vol 232 (1) ◽  
pp. E5
Author(s):  
R C Rose ◽  
D L Nahrwold ◽  
M J Koch
Keyword(s):  
Active Transport ◽  
Electrical Potential ◽  
Electrolyte Transport ◽  
Potential Profile ◽  
Ion Concentration ◽  
Transport Mechanisms ◽  
Na Transport ◽  
Concentration Gradients ◽  
Rabbit Ileum ◽  
Cation Concentration

The electrical potential profile of rabbit ileum was investigated in vitro with the microelectrode technique. The transmural electrical potential difference (PD), designated psims, was immediately reduced by 60% upon cooling the tissue from 37 to 7 degrees C; the PD across the mucosal membrane (transmucosal PD, psimc) was simultaneously reduced by 37%. These electrical changes could not be attributed to alternations in either transmembrane ion concentration gradients or total tissue conductance. The psimc and psims may have substantial values even after the concentration gradients of Na and K across the cell membane are eliminated, provided that active transport mechanisms are still operative. Conversely, in the presence of approximately normal transmembrane ion concentration gradients, but when active transport mechanisms have been inhibited. psimc is reduced by 45% and psims is zero. These observations are consistent with a model of electrolyte transport in which psims and the normal transmembrane cation concentration gradients are established by rheogenic active transport of Na out of the cell. The psimc is generated both by rheogenic active Na transport and by cation concentration gradients which exist across the cell membrane. The Koefoed-Johnsen and Ussing model (Acta Physiol. Scand., 1958, vol. 42, p. 298) of electrolyte transport by epithelial cells does not adequately describe the electrical properties of ileum.

An Exploratory Study of a Novel Peritoneal Combination Dialysate (1.36% Glucose/7.5% Icodextrin), Demonstrating Improved Ultrafiltration Compared to Either Component Studied Alone

2003 ◽  
Vol 23 (5) ◽  
pp. 475-480 ◽  
Author(s):  
Sarah B. Jenkins ◽  
Martin E. Wilkie
Keyword(s):  
Peritoneal Dialysis ◽  
Computer Simulations ◽  
Dilution Method ◽  
Initial Increase ◽  
Peritoneal Membrane ◽  
Technique Survival ◽  
Final Volume ◽  
Ultrafiltration Failure ◽  
Glucose Polymer ◽  
The Impact

Objective Concerns regarding the impact of ultrafiltration failure on peritoneal dialysis and the effect of hypertonic glucose on the peritoneal membrane have lead to a search for alternative dialysates. Computer simulations based on the three-pore theory suggest that a combination of 1.36% glucose and 7.5% icodextrin (glucose polymer) offers an improved ultrafiltration profile. The aim of the present study was to investigate the ultrafiltration profile of this combination fluid. Design Prospective open study comparing 1.36% glucose, 3.86% glucose, 7.5% icodextrin, and the combination fluid (1.36% glucose/7.5% icodextrin). Setting Sheffield Kidney Institute, Northern General Hospital, Sheffield, UK. Patients 11 patients currently using peritoneal dialysis not previously exposed to icodextrin. Main Outcome Measure Intraperitoneal volume was measured using a radioisotope dilution method. Results The combination fluid showed a biphasic ultrafiltration profile, with a steep initial increase in intraperitoneal volume, then a maintained plateau phase for the duration of the study dwell (7 hours). The final volume was greater than that with the 1.36% glucose dwell and the 7.5% icodextrin dwell. The fluid was well tolerated by the patients. Conclusions These findings are in keeping with computer simulations using the three-pore model. The combination fluid offers an improved ultrafiltration profile, with a final volume similar to 3.86% glucose, while avoiding exposing the peritoneal membrane to high glucose concentrations. It may have a role as a long dwell to optimize ultrafiltration and possibly prolong peritoneal dialysis technique survival.

scholarly journals Serum CA125 a potential marker of volume status for peritoneal dialysis patients?

2021 ◽  
pp. 039139882110168
Author(s):  
Dilushi Wijayaratne ◽  
Vasantha Muthu Muthuppalaniappan ◽  
Andrew Davenport
Keyword(s):  
Heart Failure ◽  
Peritoneal Dialysis ◽  
Left Ventricular ◽  
Volume Status ◽  
Left Ventricular Ejection ◽  
Cancer Antigen 125 ◽  
Membrane Function ◽  
Ventricular Ejection Fraction ◽  
Potential Marker ◽  
Ultrafiltration Failure

Introduction: Serum cancer antigen 125(SeCA125) has been reported to be increased in patients with heart failure and correlate with both extracellular water (ECW) overload and poor prognosis. Ultrafiltration failure and ECW overload are a major cause of peritoneal dialysis (PD) technique failure. We wished to determine whether SeCA125 could also be a marker of volume status in PD patients. Methods: We contemporaneously measured SeCA125, serum N terminal brain natriuretic peptide (NTproBNP) and ECW by bioimpedance in adult PD patients attending for outpatient assessment of peritoneal membrane function. Results: The median SeCA125 was 19 (12–33) U/mL in 489 PD patients, 61.3% male, median age 61.5 (interquartile range 50–75) years. SeCA125 was positively associated with the ratio of ECW/total body water (TBW) ( r = 0.29, p < 0.001), 4-h peritoneal dialysate to serum creatinine ratio ( r = 0.23, p < 0.001), NTproBNP) ( r = 0.18, p < 0.001), and age ( r = 00.17, p = 0.001) and negatively with 24-h PD ultrafiltration volume ( r = −0.28, p < 0.001) serum albumin ( r = −0.22, p < 0.001), and echocardiographic left ventricular ejection fraction ( r = −0.20, p < 0.001), but not with residual renal function or C-reactive protein. Patients with above the median SeCA125, had greater median ECW/TBW 0.403(IQR 0.394–0.410) vs 0.395(0.387–0.404), p < 0.001 and NTproBNP (6870 (IQR 1936–20096) vs 4069 (1345–12291) vs) pg/mL, p = 0.03. Conclusion: Heart failure studies have reported SeCA125 is a marker of ECW overload. Our retrospective analysis suggests that SeCA125 is also associated with ECW volume in PD patients. Further studies are required to determine whether serial measurements of SeCA125 trend with changes in ECW status in PD patients and can be used to aid volume assessments.

scholarly journals Clinical Epidemiology of Systolic and Diastolic Orthostatic Hypotension in Patients on Peritoneal Dialysis

2021 ◽  
Vol 10 (14) ◽  
pp. 3075
Author(s):  
Claudia Torino ◽  
Rocco Tripepi ◽  
Maria Carmela Versace ◽  
Antonio Vilasi ◽  
Giovanni Tripepi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Peritoneal Dialysis ◽  
Orthostatic Hypotension ◽  
Clinical Epidemiology ◽  
Hemodialysis Patients ◽  
Excess Death ◽  
Death Risk ◽  
Standardized Protocol ◽  
Pressure Changes ◽  
The Impact

Blood pressure changes upon standing reflect a hemodynamic response, which depends on the baroreflex system and euvolemia. Dysautonomia and fluctuations in blood volume are hallmarks in kidney failure requiring replacement therapy. Orthostatic hypotension has been associated with mortality in hemodialysis patients, but neither this relationship nor the impact of changes in blood pressure has been tested in patients on peritoneal dialysis. We investigated both these relationships in a cohort of 137 PD patients. The response to orthostasis was assessed according to a standardized protocol. Twenty-five patients (18%) had systolic orthostatic hypotension, and 17 patients (12%) had diastolic hypotension. The magnitude of systolic and diastolic BP changes was inversely related to the value of the corresponding supine BP component (r = −0.16, p = 0.056 (systolic) and r = −0.25, p = 0.003 (diastolic), respectively). Orthostatic changes in diastolic, but not in systolic, BP were linearly related to the death risk (HR (1 mmHg reduction): 1.04, 95% CI 1.01–1.07, p = 0.006), and this was also true for CV death (HR: 1.08, 95% CI 1.03–1.12, p = 0.001). The strength of this association was not affected by further data adjustment (p ≤ 0.05). These findings suggest that independent of the formal diagnosis of orthostatic hypotension, even minor orthostatic reductions in diastolic BP bear an excess death risk in this population.

scholarly journals The Impacts of Groundwater Chemistry on Wetland Vegetation Distribution in the Northern Qinghai–Tibet Plateau

2019 ◽  
Vol 11 (18) ◽  
pp. 5022 ◽  
Author(s):  
Junju Zhou ◽  
Juan Xiang ◽  
Lanying Wang ◽  
Guoshuang Zhong ◽  
Guofeng Zhu ◽  
...  
Keyword(s):  
Multiple Scales ◽  
Groundwater Chemistry ◽  
Ion Concentration ◽  
Tibet Plateau ◽  
Distribution Data ◽  
Vegetation Distribution ◽  
Chemical Parameters ◽  
Weakly Alkaline ◽  
Artemisia Frigida ◽  
The Impact

Groundwater chemistry has an important impact on the vegetation distribution in inland areas. An in-depth understanding of the impact of groundwater chemistry on vegetation can help in developing an effective management strategy to protect the inland ecosystem. The aim of this study was to identify the influence of groundwater chemicals on species diversity and the distribution characteristics of wetland plants at multiple scales based on the groundwater chemical data from 15 sampling points and the distribution data of 13 plants in the Sugan Lake Wetland in 2016. The results show that the groundwater of the Sugan Lake Wetland is weakly alkaline, with high salinity and hardness; the water chemical type is Na-SO4-Cl; the concentration of the major water chemical parameters is significantly different and is the highest in the northwest, followed by the southwest, and is the lowest in the east; with an increase in the groundwater depth, the concentration of major water chemical parameters first showed an increasing trend followed by a decreasing trend; Artemisia frigida Willd, Poa annua L. and Triglochin maritimum L. were adapted to the environment with a higher ion concentration of the groundwater, and their salt resistance was the strongest; Blysmus sinocompressus and Polygonum are more adapted to the environment with lower salinity and hardness of groundwater; Thermopsis lanceolata has stronger adaptability to the ion concentration, salinity, and hardness of groundwater; other plants are adapted to environments where the ion concentration, salinity, and hardness of the groundwater are moderate.

scholarly journals Insulin Resistance as a Predictor of Cardiovascular Disease in Patients on peritoneal dialysis

2013 ◽  
Vol 33 (4) ◽  
pp. 411-418 ◽  
Author(s):  
Yun Li ◽  
Lihua Zhang ◽  
Yong Gu ◽  
Chuanming Hao ◽  
Tongying Zhu
Keyword(s):  
Insulin Resistance ◽  
Peritoneal Dialysis ◽  
Independent Predictor ◽  
Hazard Ratio ◽  
Diabetic Patients ◽  
Model Assessment ◽  
Mortality Hazard ◽  
Cv Disease ◽  
The Impact ◽  
Mortality Hazard Ratio

BackgroundInsulin resistance is associated with multiple risk factors for cardiovascular (CV) disease in the general population. Patients on peritoneal dialysis (PD) are more likely to develop insulin resistance. However, no evaluation of the impact of insulin resistance on CV disease morbidity or mortality in patients on PD has been performed.MethodsOur prospective cohort study included all non-diabetic patients on PD at our center ( n = 66). Insulin resistance was evaluated at baseline by the homeostasis model assessment method (HOMA-IR) using fasting glucose and insulin levels. The cohort was followed for up to 58 months (median: 41.3 months; interquartile range: 34.3 months). A multivariate Cox model was used to analyze the impact of insulin resistance on CV disease mortality.ResultsFourteen CV events occurred in the higher HOMA-IR group [IR-H (HOMA-IR values in the range 2.85 – 19.5), n = 33], but only one event occurred in the lower HOMA-IR group (IR-L (HOMA-IR values in the range 0.83 – 2.71), n = 33) during the follow-up period. Level of HOMA-IR was a significant predictor of CV events [risk ratio: 17.7; 95% confidence interval (CI): 2.10 to 149.5; p = 0.008]. In the IR-H group, 10 patients died (8 CV events), but in the IR-L group, only 4 patients died (1 CV event). Patients in the IR-H group experienced significantly higher CV mortality (hazard ratio: 9.02; 95% CI: 1.13 to 72.2; p = 0.04). Even after adjustments for age, systolic blood pressure, body mass index, C-reactive protein, triglycerides, resistin, and leptin, HOMA-IR remained an independent predictor of CV mortality (hazard ratio: 14.8; 95% CI: 1.22 to 179.1; p = 0.03).ConclusionsInsulin resistance assessed using HOMA-IR was an independent predictor of CV morbidity and mortality in a cohort of nondiabetic patients on PD. Insulin resistance is a modifiable risk factor; the reduction of insulin resistance may reduce CV risk and improve survival in this group of patients.

Three-Pore Model Predictions of 24-Hour Automated Peritoneal Dialysis Therapy Using Bimodal Solutions

2011 ◽  
Vol 31 (5) ◽  
pp. 537-544 ◽  
Author(s):  
Alp Akonur ◽  
J. Ken Leypoldt
Keyword(s):  
Peritoneal Dialysis ◽  
Glucose Absorption ◽  
Patient Transport ◽  
Pore Model ◽  
Low Concentrations ◽  
Baxter Healthcare ◽  
All Solutions ◽  
Model Predictions ◽  
Fast Transport ◽  
Transport Type

BackgroundRecently, bimodal peritoneal dialysis (PD) solutions containing low concentrations of Na have been shown to increase 24-hour ultrafiltration (UF) or UF efficiency (UF volume per gram of carbohydrate or CHO absorbed) and Na removal in high (“fast”) transport patients during automated PD therapy. We used computer simulations to compare UF efficiency and Na removal at equivalent 24-hour UF volumes using either a generic bimodal solution (2.27% glucose + 7.5% icodextrin) during the long dwell or an increase in the glucose concentration during the short dwells, with all solutions containing Na at the conventional concentration (132 mEq/L).MethodsThe 3-pore model has been shown to accurately predict peritoneal transport for PD solutions containing glucose or icodextrin, or both. Here, we used that model to calculate 24-hour UF volume, CHO absorption, and Na removal for high (H), high-average (HA), and low-average (LA) transport patients on automated PD. Nighttime therapy consisted of 1.36% or 2.27% glucose solution (or both), and daytime therapy consisted of either Extraneal (Baxter Healthcare Corporation, Deerfield, IL, USA) or a bimodal solution.ResultsAs expected, addition of glucose to either the long dwell or the short dwells resulted in increased UF volume and glucose absorption. The increase in UF was a function of patient transport type (bimodal range: 288 – 490 mL; short-dwell range: 323 – 350 mL), and the increase in CHO absorption was smaller with glucose added to short dwells than with bimodal solution (range: 18 – 30 g vs. 34 – 39 g). The 24-hour UF efficiency was higher when high glucose concentrations were used during short-dwell exchanges than when a bimodal PD solution was used for the long dwell (0.6 to 1.2 mL/g vs. –0.1 to 0.5 mL/g). By contrast, Na removal was lower with the short-dwell exchanges (28.3 – 30.7 mmol vs. 36.2 – 53.3 mmol), likely because of more pronounced Na sieving.ConclusionsOur modeling studies predict that generic bimodal PD solutions will provide higher Na removal but not higher 24-hour UF efficiency compared with current automated PD prescriptions using Extraneal for the long dwell and glucose-containing solutions for the short dwells. The modeling predictions from this study require clinical validation.

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